Electrolytic device



Nov. 8, 1938. J. B. BRENNAN 2,135,492

ELECTROLYTIC DEVICE Filed Aug. 14, 1955 2 Sheets-Sheet l Zhmentor 70557 B- EBE/ IVA /V Qttornegs Nov. 8, 1938. J. B. BRENNAN ELECTROLYTIC DEVICE Filed Aug. 14, 1935 2 Sheets-Sheet 2 M H a B M w J Patented Nov. 8, 1938 UNITED STATES PATENT OFFICE 5 Claims.

This invention relates to electrolytic condensers and similar devices, and more particularly to a spacer for preventing contact between the electrodes of an electrolytic condenser.

In electrolytic condensers of the paste type wherein the electrodes comprise thin sheets of aluminum or other suitable material rolled into cylindrical form, as well as in electrolytic condensers of the liquid type, it is essential to prevent actual contact between the electrodes and at the same time to arrange the electrodes close together to reduce the resistance of the electrolyte. Thus a separator of suflicient strength, stiffness and thickness to prevent contact between the electrodes is required, and at the same time the separator must not be damaged by the ordinary heat of operation of the condenser and must be of such character that it will not increase the resistance of the condenser to any material extent, and will not contaminate the electrolyte, or have any other damaging effect on the condenser.

It is among the objects of my invention to provide a spacer for electrolytic condensers having the desirable characteristics noted above, and which can be produced economically and rapidly. Another object of my invention is to provide a method of making such a spacer. A further object is the provision of a spacer which will function to retain the electrolyte between the electrode plates of the condenser. Another object is to provide an inert spacer which will be substantially unaffected by the heat of operation in the condenser, and which will retain its desired characteristics for long periods of time. Another object is to provide a spacer which can be readily handled and easily assembled in a condenser. Another object is the provision of a separator having suflicient strength and stiffness effectively to separate the condenser plates. A further object is the provision of apparatus to make the spacer material referred to in the above objects. A further object is the provision of an electrolytic condenser which will have long life and which will operate eiiiciently under various conditions.

Further objects and advantages of my invention will become apparent from the following description of preferred forms thereof. The essential characteristics are summarized in the claims.

In the drawings Figure 1 illustrates a paste type condenser made according to my invention, the condenser being partially unrolled to illustrate the internal construction thereof. Figure 2 is a cross-sectional view of a liquid type of condenser embodying a spacer made according to my invention. Figure 3 is a plan view of a preferred form of spacer material. Figure 4 is a view similar to Figure 3 but on a large scale. Figure 5 is a section taken along the line 5-5 of Figure 4. Figure 6 is a plan view of my spacer during an intermediate stage in the manufacture thereof, and Figure '7 is a diagrammatic illustration of apparatus which may conveniently be employed for producing my spacers. Figure 8 illustrates an alternative form of apparatus for producing the spacer material. Figure 9 illustrates a corrugating mechanism which may be incorporated in the devices shown in Figures 7 and 8.

Briefly a spacer made according to my invention preferably comprises a thin sheet of reticulated fibrous material such as fabric netting or perforated paper in which the individual strands or threads forming the sheet or the paper defining the perforations are coated or encased in a layer of material which is impervious to the electrolyte and which is not effected by the electrolyte or by the heat which may be developed in the condenser in use. I have found cotton fabric netting of 10 to 40 mesh to be suited for my purpose, and preferably I coat the threads making up the netting with material such as rubber latex, nitrocellulose lacquers, or lacquer emulsions.

In order rapidly and conveniently to coat the material I have found it advantageous merely to pass a web of the material continuously through a tank containing the coating solution. The reticular material ordinarily retains a film of the coating material in the open spaces therein, and in order to remove the film or windows thus formed and produce an open network, I preferably blow the excess material out of the open spaces with a blast of compressed air or other suitable gas. The'material with the coating remaining thereon after the blowing operation is then allowed to dry after which it can conveniently be assembled in condensers. Prior to assembly the material may be subjected to heat and pressure treatment as, required by the particular fabric coating substance. In some types of condensers I have found it advantageous to run the material through hot corrugating rolls to give the spacer greater effective thickness.

Referring now to the drawings, in Figure 1 I have illustrated a paste type condenser. This condenser is of a well known type and may comprise two aluminum plates lli and II, one or electrolytic pastes may be employed if desired.

After the electrode plates, separators, terminals and paste are assembled together the whole may be rolled into cylindrical form, as illustrated at l6.

In Figure 2 of the drawings I have illustrated the application of my separator to a liquid type of condenser which may comprise a container 20 which also forms the cathode of the condenser, an anode 2i within the container 20 and immersed in the electrolyte 22, and a separator 23 to prevent the anode from touching the cathode.

The anode may be supported by a riser 24 extending through a neck 25 formed integrally with the container 20, the neck being compressed inwardly against a rubber gasket or sleeve 28 to form a seal between the riser and the neck.

In either case, my separator preferably comprises the netting illustrated in Figures 3, 4 and 5 of the drawings, and consisting of interwoven strands or threads 30 and iii woven to leave spaces indicated at 32. I have found that cotton fabric netting of about ten to forty open spaces per inch provides a low cost and efficient base material for the spacer. The netting selected should be free from impurities such as chlorides and sulphates which would adversely effect the electrolyte. It will be noted that the area of the spaces 32 is great as compared-to the area of the strands 30 and 3!, and thus the spacer will not materially increase the resistance of the condensers.

In order to strengthen or stiffen the material of the spacer and also to gain a slight additional thickness in the spacer, the individual threads or strands 30 and 3| thereof are encased in a material which is impervious to the electrolyte, and which will not contaminate the electrolyte nor be affected by the heat generated in a condenser. The completed construction is illustrated on a greatly enlarged scale in Figures 4 and 5, wherein it will be seen that each of the strands 30 and 3| is encased by a layer 33 of protective material. Preferably the material comprises a nitrocellulose lacquer, a lacquer emulsion, or rubber latex, although various other suitable inert materials may be employed such as resin varnishes of the phenol formaldehyde or urea formaldehyde type. The coating material selected should preferably be free from soluble chlorides or sulphates or other free impurities,

It will be seen that by so cncasing the individual strands in an impervious material, the coated material becomes relatively rigid which adds to its strength and facilitates handling throughout the steps of manufacture such as cutting and rolling. Furthermore, it is not necessary that the coating permeate the material of the strands so long as the strands are completely encased in an impervious covering. By reason of this fact the coating can be carried out at high speed, as it is not necessary to allow sufficient time for the strands individually to become impregnated with the coating material.

Thus the coating operation can be carried out rapidly and expeditiously with the apparatus illustrated diagrammatically in Figure '7, which may comprise a roll 34 of untreated netting 25 mounted on a suitable support, the netting being guided by rollers 36, 31 and 38 through a bath of the coating material contained in a tank 39. As the netting emerges from the tank the coating material ordinarily forms a film or window" in many if not all of the interstices 52 of the netting, thus producing the appearance diagrammatically illustrated in Figure 6, wherein the shading shows a thin film of coating material carried in the interstices 32. To remove the film and break the "windows formed thereby the coated material 35 may be passed in front of a jet or nozzle 40 through which a blast of compressed air is discharged, although suction may be employed if desired. The air blows the excess material against a baffle or plate 45 arranged to conduct liquid back into the tank 39. This leaves each strand or thread of the netting in the web. with a fairly uniform protective coating. Thereafter the web is passed over the pulley 4| and is allowed to travel along in the air for a sufficient distance for it to dry, and then it is coiled on the reel 42.

An alternative form of producing the spacer material is shown in Figure 8 wherein a storage roll 50 is arranged to feed material over guiding rolls 5l5253 through the tank 55 containing the coating liquid 54. The wet fabric Bil is conducted over a drum or roll 55 having a smooth outer surface. The him of coating liquid forming the windows tends to stick to the surface of the drum and thus are broken as the fabric is pulled from the drum by the guiding roll 58. A wiper blade or brush 51 is arranged to remove the liquid from the surface of the drum and conduct it back to the tank 55.

It will be understood that the spacer fabric made according to my invention is well suited to corrugating in order to increase the effective thickness thereof and may be passed through corrugating rolls 65 and 68 as shown in Figure 9. The rolls are preferably heated slightly to facilitate the corrugating process and electric heating means are indicated diagrammatically at 61 and 68.

It will be noted that the coating materials which I employ, that is lacquer, lacquer emulsions, rubber latex or other rubber solutions or various resin varnishes, may be applied cold, and when once hardened will not be materially softened by the heat of operation developed in the condenser.

From the foregoing description of the preferred form of my invention, it will be seen that I have provided a spacer for electrolytic condensers which can be manufactured rapidly and economically from inexpensive materials. My spacers are substantially unaffected by the heat of operation or by the ingredients of the electrolyte. Also my spacers effectively separate the electrodes of condensers to which they are applied, and at the same time do not materially increase the resistance of the condensers in which they are incorporated. Thus condensers made according to my invention operate efficiently, are rugged and sturdy, and have long life and high break-down voltage characteristics.

Various modifications and changes within the scope and spirit of my invention will be apparent to those skilled in the art. For example, different materials may be employed as the base of the netting to which the coating is applied. Different coating materials may be used provided they are impervious, non-conductive and substantially unaffected by the electrolytes incorporated in the condenser, and provided they are substantially unaffected by the heat developed in the condenser in ordinary service. I have described my invention with reference to electrolytic condensers of two well known types, but it will be evident to those skilled in the art that my invention may be embodied in condensers of different types as well as in other electrolytic devices. Therefore, it is to be understood that my invention is not limited to the preferred form described herein, or in any manner other than by the scope of the appended claims when given the range of equivalents to which my patent may be entitled.

I claim:

1. An electrolytic condenser comprising a pair of electrodes and a spacer arranged between the electrodes, said spacer comprising a reticular iabric encased in one of the materials from the group consisting of lacquer, lacquer emulsions, latex, condensation products of urea and formaldehyde, and condensation products of phenol and formaldehyde.

2. In an electrolytic condenser of the dry or paste type having a pair of electrodes, a spacer disposed between said electrodes and comprising a sheet of fibrous material impregnated with a condensation product of urea and formaldehyde.

3. An electrolytic condenser comprising apair of electrodes, an electrolyte, and a spacer arranged between the electrodes and immersed in the electrolyte, said spacer comprising a fabric netting having the individual threads thereof encased in one of the materials from the group consisting of lacquer, lacquer emulsions, latex, condensation products of formaldehyde and phenol, and condensation products of formaldehyde and urea.

4. An electrolytic condenser comprising a pair of electrodes, an electrolyte, and a spacer arranged between the electrodes and immersed in the electrolyte, said spacer comprising a corrugated iabric netting having the individual threads thereof encased in one of the materials from the group consisting of lacquer, lacquer emulsions, latex, condensation products oi formaldehyde and phenol, and condensation products of fcrm-.

aldehyde and urea.

5. A reticulated inner spacer for use in electrolytic condensers comprising spaced transversely arranged fibers encased in a material from the group consisting of lacquer, lacquer emulsions, latex, condensation products of urea and formaldehyde, and condensation products of phenol and formaldehyde.

JOSEPH B. BRENNAN. 

